So, my two guys, Gershwin (10 yrs approximately) and Tristan (2 years approximately) have been THE BEST buddies since they were united. They sleep together, groom each other, play together, and generally exist together peacefully.So, just a few minutes ago, I broke up the second terrible, spitting, snarling, scary confrontation in a couple days. It starts out with Tristan being his usual super playful self, then maybe a game of tag-you're-it ensues, and then Gershwin takes it to this really scary level and starts SPAZZING - spitting, snarling, screaming - like he's out to kill Tristan. And of course Tristan gets very scared, runs to hide under the bed, and Gershwin follows him (he can't fit under the bed though) and stands bedside snarling, hissing and screaming. This is the point where I've been able to jump in and break it up both times. Gershwin is currently quarantined in our bedroom, while Tristan is out in the rest of the apartment, terrified, skittish and really upset. It's terrible to see. :(

What the flying fork has happened? I don't understand why this has happened twice now.Gershwin has always been very antisocial and scary-mean towards humans that aren't me or T., but now his own brother?

_________________Did you notice the slight feeling of panic at the words "Chicken Basin Street"? Like someone was walking over your grave? Try not to remember. We must never remember. - mumblesIs this about devilberries and nazifruit again? - footface

I bet Tristan is reaching maturity and starting to challenge Gershwin's dominance and he doesn't like it...you might want to separate them for a week or two and then reintroduce them, get a Feliway diffuser maybe, and maybe read the book Cat vs Cat? I think it's helpful.

_________________"No one with hair so soft and glossy could ever be bad at anything." - Tofulish

Has Tristan done anything recently that would make him smell different? I had to take Luna and Dexter to the vet a few months ago, separately, and they both smelled different afterwards and basically wanted to kill each other. I had to quarantine like you did and I spent a bunch of money on Feliway until they fell back in love and got used to each other. So my first thought is smell.My other thought is that maybe Gershwin isn't feeling good and it is making him irritable. Is he showing any other signs that something could be wrong?

I bet Tristan is reaching maturity and starting to challenge Gershwin's dominance and he doesn't like it...you might want to separate them for a week or two and then reintroduce them, get a Feliway diffuser maybe, and maybe read the book Cat vs Cat? I think it's helpful.

I would definitely take the older cat to a vet to make sure there's nothing wrong physically. If he's not feeling well or in pain, he could be aggressive because he doesn't want the younger cat jumping on him or jostling him (older cats get arthritis just like dogs, but they usually don't show symptoms as clearly as dogs do, so many cats never get the diagnosis and treatment they need). Once physical problems are ruled out, you can work on behaviour. There's a great show on Animal Planet called "My Cat from Hell" and they just had an episode on cats with a similar problem. The cats had been getting along for a while, but then began fighting. The solution was to separate them for a while and then slowly introduce them, just like you would when bringing a new cat home.

Thanks for all your insight, everyone! Looks like ol' Gershwin is gonna get to go to the vet this week (his favourite!...I mean, his absolute-worst-thing-ever!) to make sure he is okay in every way. My baby. He's always been grumpy, but never towards his baby brother.

If it persists, I'm going to try the reintroduction thing.

Here's the grumpster himself, being floofy like usual:

And here's Tristan being naughty as usual:

_________________Did you notice the slight feeling of panic at the words "Chicken Basin Street"? Like someone was walking over your grave? Try not to remember. We must never remember. - mumblesIs this about devilberries and nazifruit again? - footface

I would definitely take the older cat to a vet to make sure there's nothing wrong physically. If he's not feeling well or in pain, he could be aggressive because he doesn't want the younger cat jumping on him or jostling him (older cats get arthritis just like dogs, but they usually don't show symptoms as clearly as dogs do, so many cats never get the diagnosis and treatment they need). Once physical problems are ruled out, you can work on behaviour. There's a great show on Animal Planet called "My Cat from Hell" and they just had an episode on cats with a similar problem. The cats had been getting along for a while, but then began fighting. The solution was to separate them for a while and then slowly introduce them, just like you would when bringing a new cat home.

I love that show! Several times they have featured a cat who starts acting out, seemingly out of nowhere, and it turns out he or she had a physical problem and was in pain. It was so obvious with this one cat - she would lash out if someone touched her back side and even before Jackson said anything, my first thought was that cat is hurting. When her people finally took her to the vet, they found out the poor dear had arthritis. Once she got treatment, her behavior improved.

_________________Again, you are all brilliant and sexy. And I am lavender-laden and secure in my masculinity. - Sir Brancis Facon